The present invention is directed to an auxiliary damper for use with rubber or other spring suspension mountings. More particularly, the present invention is directed to an auxiliary surface-effect damper that can be confined within the existing space envelope occupied by the primary suspension mounting.
Laminated rubber and metal mounts have been around for some time. In addition, the focalization of elastomeric mounts has been employed to decouple the translational and rotational vibrational modes in order to greatly simplify the required mounting system needed to provide the necessary damping and isolation.
The present invention proposes to add auxiliary damping to a system to reduce movement at or near the system's resonance frequency. The system may employ an elastomeric spring mount or other type of spring mount in the primary suspension, and preferably will include focalization. An elastomeric sleeve bonded to a rigid collar that surrounds a support bolt for a pair of primary mounts provides a workable surface element for surface-effect (frictional and hysteretic, combined) damping. The bolt secures the primary suspension mountings and auxiliary damper to a first one of a supported element and a support. A metallic sleeve which has a C-shaped cross section and an internal peripheral surface which has cylindrical protrusions formed thereon surrounds the elastomeric sleeve and the protrusions work the elastomer to dissipate energy by hysteresis. The upper flange of the C-shaped sleeve overlies and the lower flange underlies the other of the supported element and the support.
Most preferably, the distance between the flanges exceeds the maximum thickness of that other member and the outer diameter of the central portion of the C-shaped member is smaller than the diameter of the opening in the support. This clearance between the sleeve and its received member permit vibrations of low amplitude, high frequency to be isolated (i.e., not transmitted) from the support vis-a-vis the supported element. When the vibration of the support exceeds this minimally permitted magnitude as, for example, when the disturbance frequency approaches the natural, or resonant, frequency of the system, the auxiliary damper will dissipate the objectionable motion-inducing energy and restore controlled movement between the supported element and the support.
Various features, advantages and characteristics of the present invention will become apparent after a reading of the following specification.